"Preface to the Pavilion of King Teng" says that the moment when Prince An ascended to compose a Fu, there were four beauties, and the two were difficult to combine, which means that it was a good day, beautiful scenery, pleasing to the eye, and pleasure. The perfect moment, so it has created a good work that spans the past and the present.

　　Following the footsteps of the sages, STEP's industrial control designers have been on the road of pursuing perfection. After more than ten years of unremitting technological transition and product iteration, and the accumulation of a large number of on-site demand changes in the industry, this four-beautiful AS720D is dedicated to the guests of the refrigeration industry. Which four beauties?

　　First beauty | extremely high power density

　　AS720D inherits the extremely high power density of AS720 and is developed on the basis of the original product. It adopts non-standard custom-made cabinets and supports the on-board integrated installation of central air-conditioning compressors. The power of 630KW is only the size of a chest of drawers. However, engineering inverters with the same power in the market are generally bulky, see the comparison in the figure below.

　　Second Beauty | Low Harmonic Feedback Front-End Rectification Device

　　AS720D integrates a low-carbon energy-saving low harmonic feedback front-end rectification device. In such a compact cabinet, STEP spared no expense and built an expensive four-quadrant active front end. It not only has the same 6 groups of IGBTs as the inverter unit as the rectification unit, but also is equipped with advanced and complete LCL filtering device, independent Advanced AFE control unit and soft control system. So when you open the cabinet door, you will find that there are two handhelds inside, which are obvious double-headed dragons. This kind of design is friendly to the grid waveform, so that users can achieve a very high energy saving rate, and at the same time reduce the harmonic content of the grid to below 4%. To use a metaphor, the general inverter uses brute force to drive the maglev screw compressor to run at super high speed, while the AS720D is like a Tai Chi master turning a Tai Chi ball. Balance with energy saving, low carbon and noise reduction. Compared with ordinary frequency converters, there is a huge difference in its technical content and manufacturing cost.

　　Sanmei | AS720D adopts refrigerant cooling

　　Due to the use of four-quadrant technology, the switching frequency is high and the heat flux density is close to twice that of the traditional two-quadrant inverter. Whether it can achieve high energy efficiency ratio and improve power density depends on the cooling system. The traditional engineering frequency converter adopts air-cooling cooling method, and a large air duct needs to be designed for it, resulting in high working noise and easy adsorption of dust and sludge, etc., requiring frequent maintenance and low heat dissipation efficiency; later developed a water-cooled frequency converter, water-cooled The heat exchange efficiency is much higher than that of air cooling, but the water cooling system must be equipped with a chiller to quickly cool the circulating water, which not only consumes excess power, but also makes a lot of noise. After long-term use, scale may form in the cooling water circuit, which will reduce the thermal efficiency and make cleaning troublesome. Since the AS720D is driven by a refrigeration compressor, it is very convenient to use refrigerant for cooling, and the cooling efficiency is extremely high. Compared with water cooling, one cooling system is used, and all the above problems are avoided. In addition to achieving low noise, the greatly reduced volume makes the original 110 -The 630KW behemoth has become a small backpack on the back of the compressor to achieve airborne installation, which greatly facilitates the customer's on-site installation and application, and brings more space saving and design flexibility to the final customer.

　　Simei | AS720D has a variety of protection grade products to choose from

　　AS720D has various protection grades of IP22/IP54/IP55 to choose from. According to the different needs of customers, it can be directly installed outdoors, becoming the patron saint of central air-conditioning. And for some American standard 460V rated voltage motors, only 380V input can be used, and this machine provides a stable boost function. This greatly enriches the customer's choice of motors, as well as the compatibility of original equipment upgrades.

　　In addition to the four beautiful products of the products, the STEP HVAC service team also provides on-site product installation and maintenance services of "original care, professional home", to further meet customers' requirements for long-term use and reliable operation, and fully follow the virtuous Lord's way of respecting customers.

　　Youdao is the master of Yake Laiqin. In the face of the still raging autumn tiger, let AS720D match with magnetic levitation, air levitation, and high-speed direct-drive units to keep the heat in a cage and let the industry take a big step towards the goal of low-carbon emission reduction. . Achieve a perfect application of four beauties and two difficulties, what do you think?